Just a few quick questions - is it a DSL service? That sort of bad connection on the first hop is quite often just a poor copper connection - ensure that the filter is replaced to the router and it could just be the local cables.

Also if a DSL service if you disconnect your router for >30 minutes then the DSLAM card at the exchange end will reset the connection profile and it should hopefully re-establish the potential speeds for that circuit.

Sorry its been a while since I did anything WAN/internety as I now just concentrate on systems so I might have just sprouted a load of crap...